Describe the properties of metals
- high melting + boiling point
- ductile (pulled into wires)
- good conductors
- solid at room temp
Describe the properties of non-metals
- low melting + boiling points
- half are solid, half are gas at room temp
What are elements arranged in order of on the periodic table?
Atomic number (num. of protons and electrons)
define the periodic table
a table in which elements are arranged in columns and periods in ascending order of atomic number
where are metal elements placed in a periodic table?
on the left hand side
where are non-metals placed on a period table?
on the right hand side
what happens when metals become ions?
do metals react with each other?
- metals lose electrons to form ions
- metals do not react with each other (mix to form alloys)
as they both would like to gain electrons, so no reaction happens
what happens when a non metal forms an ion?
can non-metals react with each other?
- non-metals gain electrons when forming ions
- yes, they form covalent bonds
what kind of solutions do metal oxides produce in water?
what kind of solutions do non metals form in water?
what is a horizontal row in the periodic table called?
what is the column in the periodic table called?
what are ions?
an ion is an electrically charged particle formed when an atom or group of atoms lose or gain electrons
how do you represent an electron diagram?
draw a circle to represent each shell
how do ionic compounds form?
- metal reacts with a non-metal
- electrons are transferred from the metal atoms to the non-metal atoms
- both achieve full outer shells (more stable)
what is the structure of an ionic compound?
giant ionic lattice (regular arrangement of positive and negative ions)
what are ionic bonds?
strong electrostatic forces between oppositely charged ions
what does the word ‘giant’ mean in ‘giant ionic lattices’?
the arrangement is repeated many times
what does the word ‘lattice’ mean in ‘giant ionic lattice’?
that the arrangement is regular and not random
what is a covalent bond?
a shared pair of electrons
how do covalent bonds form?
when two non-metal atoms share electrons in their outer shells
what does the intersection of a covalent bond diagram represent?
shared pair of electrons (bond itself)
When drawing a covalent bond diagram, how many shells are drawn?
Only the outer one
what is the bonding of simple molecules like?
- electrostatic forces of attraction between nucleus and shared electron
- covalent (electrostatic force) between atoms = strong
- intermolecular forced between molecules = weak
State two limitations of ball and stick diagrams
- size of atoms are exaggerated
- length of bonds are exaggerated
- suggests that electrons that make the bonds do not move
how is the chemical formula of a giant ionic and covalent molecules shown?
using the empirical formula (simplest whole number ratio of atoms)
what are giant covalent structures?
- many repeating non-metal atoms joined by covalent bonds and arranged in a repeating regular pattern
- called giant lattice
Order the following bonds depending on how high their melting/boiling points are : Covalent Bond Inter molecular forces Ionic Metallic
Inter Molecular Forces
what do intermolecular forces do?
what is the strongest bond possible?
Do Giant ionic lattices have intermolecular forces, ionic bonds or covalent bonds?
Do Giant covalent lattices have intermolecular forces, ionic bonds or covalent bonds?
- ONLY covalent bonds
compare a giant ionic structure with a giant covalent structures
- both are repeated in a regular pattern
- both are repeated many times
Why do giant ionic lattices only have such a high boiling point?
as ionic bonds are very strong so a high amount of energy is needed to break them
Describe the structure in metals
- forms giant metallic lattice
- regular pattern
what is metallic bonding?
- electrostatic forces of attraction between
delocalised electrons + positive metal ions
Would it be easy to represent a giant covalent structure using a dot and cross diagram?
no because there are many atoms (almost too many to draw)
What force acts between metal and non-metal ions?
electrostatic forces (ionic bonding)
what is a delocalised electron?
an electron which is free to move about between different positive metal ions (within a giant metallic lattice)
Why are metals good conductors of electricity and heat?
has delocalised electrons that can move around
why are metal alloys stronger than pure metals?
- the different sized atoms disrupt the regular arrangement of atoms (which stops the various layers from sliding over one another)
how did Mendeleev arrange known elements in his periodic table?
- in terms of their atomic mass
- in terms of similar chemical properties
how did Mendeleev predict the properties of unknown elements?
by looking at the elements around it
how was Mendeleev’s first periodic table arranged?
in rows and not columns
why did Mendeleev arrange the periodic table in terms of atomic masses?
because protons had not been discovered yet
who discovered that an element’s atomic number was actually the number of protons in its nucleus?
Why had Mendeleev swapped tellurium and iodine around?
and why was he correct to do so?
- he felt as if it ‘suited’ their chemical properties better
- because tellurium had a higher number of protons to iodine (even though its mass was not)
what was Mendeleev reluctant to believe?
that helium and argon were elements (because he thought that elements should be able to react with other elements - but they are inert)
what do group 0 elements all have in common?
they are inert (do not react to other elements)
do elements become more or less reactive as you go down in group 1 and 2?
do elements become more or less reactive as you go down in group 7?
is group 1 reactive?
is group 2 reactive?
is group 7 reactive?
is group 0 reactive?
no, not at all (inert)
why are group 0 elements unreactive?
have complete outer shells, so they have no tendency to lose, gain, or share electrons.
why are metals found in the left of the periodic table?
as they have fewer electrons in their outer shells
what are ionic bonds?
electrostatic forces of attraction between a non-metal and metal ion
what are polymers made of?
what bond joins monomers together to make polymers?